18D-29 |
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M.-J. CHEN, C.-W. Lin, and W.-S. Hong. Dept. of Animal Science, National Taiwan Univ., No. 50 Lane 155 Sec. 3. Keelung Rd., Taipei, 106, Taiwan Bifidobacteria are widely used as starter cultures in the dairy industry. Detecting and identifying various species of Bifidobacteria with a rapid method are often important for quality control of dairy products and for monitoring fermentation processes. However, the rapid identification of strains of closely related species is still a difficult task. In this paper, a rapid and reliable gene-targeted species-specific polymerase chain reaction (PCR) technique based on a two-step process was established to identify Bifidobacteria in dairy products. The first step was PCR assay for genus Bifidobacterium with genus specific primers followed by the second step, which identified the species level with species-specific primer mixtures. Twenty specific primer sets were developed for each of the Bifidobacterium species including B. angulatum, B. bifidum, B. longum, B. infantis, B. animalis B. minimum, B. suis, B. thermophilum, B. subtile and Bifidobacterium breve, they were designed from nucleotide sequences of the 16 to 23S rRNA region. Additional DGGE and phenotype methods including Gram stain, catalase test and API kit system were applied to confirm the results for species identification. This technique was applied to the identification of Bifidobacterium species isolated from more than a dozen of dairy products and six different Bifidobacterium spp.(B. angulatum, B. bifidum, B. longum, B. infantis, B. animalis and B. breve) were identified. The results indicated that using the 16S-23S rDNA gene-targeted species-specific PCR technique is a simple, rapid and reliable method for identification of Bifidobacteria in dairy products.
Session 18D, Food Microbiology: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |